Publications by authors named "Suzanne Schneider"

58 Publications

Helpful or harmful? The impact of the ketogenic diet on eating disorder outcomes in type 1 diabetes mellitus.

Expert Rev Endocrinol Metab 2022 Jul 24;17(4):319-331. Epub 2022 Jun 24.

Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK.

Introduction: Eating disorders (EDs) are common complications in people with type 1 diabetes (PwT1D), given the rigid focus on food and insulin dose adjustment. Dietary recommendations for T1D match those for the general population, yet many fail to achieve target HbA1c. Evidence suggests that lower carbohydrate meals and thus reduced insulin requirements may decrease inconsistencies in insulin absorption, maintain euglycemia and weight. Dietary restriction is a recognized risk factor for ED development, and Ketogenic Diets (KD) involve restriction of common family-based foods, thus impacting social normality and microbiome diversity. We reviewed the current literature on PwT1D following a KD to understand effects on ED risks.

Areas Covered: Published data from MEDLINE, Embase, and PsycINFO were used. Search terms included: type 1 diabetes mellitus; or insulin dependent diabetes or T1D AND EDs or anorexia or bulimia or disordered eating AND low-carbohydrate diet or carbohydrate restricted diet or low carb diet or ketogenic diet.

Expert Opinion: Research into the effects of KDs on ED outcomes in PwT1D are limited, given the concerns over risks of diabetic ketoacidosis, hypoglycemia, and dyslipidemia. Longer term studies on the participants' experience and motivations of adhering or admonishing the diet are needed.
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http://dx.doi.org/10.1080/17446651.2022.2089112DOI Listing
July 2022

Ibuprofen: Fish Short-Term Reproduction Assay with Zebrafish (Danio rerio) Based on an Extended OECD 229 Protocol.

Environ Toxicol Chem 2020 08 8;39(8):1534-1545. Epub 2020 Jul 8.

Eurofins Agroscience Services, Easton, Maryland, USA.

A study was conducted to understand the potential for ibuprofen to impact the hypothalamus-pituitary-gonadal endocrine axis resulting in disruption of fish reproduction. The Good Laboratory Practice study was conducted according to the Organisation for Economic Co-operation and Development 229 Protocol, Fish Short-Term Reproduction Assay, and extended an additional 4 d to evaluate hatching success in the F1 generation. Test organisms were exposed to nominal test concentrations of 0.5, 2.4, 11.5, 55.3, and 265.4 µg ibuprofen/L and a negative control (dilution water). To strengthen the statistical power of the study, twice the number of replicates were used in the negative control versus individual treatment levels. A 21-d pre-exposure to identify groups of actively spawning fish was immediately followed by a 36-d exposure. Results for apical endpoints of survival, growth, and reproduction (fecundity and fertility), as well as the biomarker vitellogenin in the F0 generation and time to hatch and hatching success in the F1 generation are presented. Based on mean measured exposure concentrations and effects on fecundity in the F0 generation and hatching success in the F1 generation, overall no-observed-effect concentration and lowest-observed-effect concentration for the present study were 55.2 and 265.9 µg ibuprofen/L, respectively. Results from the present study indicate a lack of endocrine-mediated reproductive effects in zebrafish at environmentally relevant concentrations of ibuprofen. Environ Toxicol Chem 2020;39:1534-1545. © 2020 SETAC.
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http://dx.doi.org/10.1002/etc.4742DOI Listing
August 2020

Development of an in vitro diagnostic method to determine the genotypic sex of .

PeerJ 2019 1;7:e6886. Epub 2019 May 1.

Aquatic Department, Performing Laboratory, Eurofins EAG Agroscience, LLC, Easton, MD, USA.

A genotypic sex determination assay provides accurate gender information of individuals with well-developed phenotypic characters as well as those with poorly developed or absent of phenotypic characters. Determination of genetic sex for can be used to validate the outcomes of Tier 2 amphibian assays, and is a requirement for conducting the larval amphibian growth and development assay (LAGDA), in the endocrine disruptor screening program (EDSP), test guidelines. The assay we developed uses a dual-labeled Man probe-based real-time polymerase chain reaction (real-time PCR) method to determine the genotypic sex. The reliability of the assay was tested on 37 adult specimens of collected from in-house cultures in Eurofins EAG Agroscience, Easton. The newly designed -specific primer pair and probe targets the DM domain gene linked-chromosome W as a master female-determining gene. Accuracy of the molecular method was assessed by comparing with phenotypic sex, determined by necropsy and histological examination of gonads for all examined specimens. Genotypic sex assignments were strongly concordant with observed phenotypic sex, confirming that the 19 specimens were male and 18 were female. The results indicate that the Man® assay could be practically used to determine the genetic sex of animals with poorly developed or no phenotypic sex characteristics with 100% precision. Therefore, the Man® assay is confirmed as an efficient and feasible method, providing a diagnostic molecular sex determination approach to be used in the amphibian endocrine disrupting screening programs conducted by regulatory industries. The strength of an EDSP is dependent on a reliable method to determine genetic sex in order to identify reversals of phenotypic sex in animals exposed to endocrine active compounds.
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http://dx.doi.org/10.7717/peerj.6886DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6500372PMC
May 2019

A pulsed-dose study evaluating chronic toxicity of chlorothalonil to fish: A case study for environmental risk assessment.

Environ Toxicol Chem 2019 07 19;38(7):1549-1559. Epub 2019 Jun 19.

EAG Laboratories, Easton, Maryland, USA.

Chlorothalonil is a fungicide which is highly toxic to aquatic organisms. However, in natural aquatic environments, it is very rapidly degraded, with a half-life typically in hours, reducing exposure of aquatic organisms and the potential for effects. In standard regulatory studies looking at the chronic toxicity of chlorothalonil to fathead minnow, the most sensitive endpoint was fecundity. A standard fish full-life cycle study, where chlorothalonil concentrations were maintained constant throughout, resulted in a no-observed-effect concentration (NOEC) of 1.4 µg/L. Comparing peak modeled exposure concentrations to this NOEC can result in the chronic risk to fish being considered unacceptable. The present study investigated the effect on fecundity in fathead minnow using a fish short-term reproduction assay. Five different exposure profiles were employed with time-varying concentrations based on realistic worst-case modeled environmental exposure profiles, multiplied by an assessment factor of 10, which resulted in maximum measured concentrations up to 15.5 µg/L. There were no effects on fecundity from any of the exposure profiles tested. Therefore, based on these more realistic exposure profiles, the chronic risk to fish could be considered acceptable if these exposures were deemed to be representative of the worst case. Environ Toxicol Chem 2019;38:1549-1559. © 2019 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.
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http://dx.doi.org/10.1002/etc.4421DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6851820PMC
July 2019

Extended fish short term reproduction assays with the fathead minnow and Japanese medaka: No evidence of impaired fecundity from exposure to atrazine.

Chemosphere 2018 Aug 16;205:126-136. Epub 2018 Apr 16.

Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, Canada.

Short-term reproduction assays were conducted with fathead minnow (Pimephales promelas) and Japanese medaka (Oryzias latipes) to evaluate responses from atrazine exposure at environmentally relevant concentrations and above. Breeding groups of fish with multiple males and females were exposed to atrazine under flow-through conditions. Fathead minnows were exposed to mean measured concentrations of 1.0, 10, 26, 52, and 105 μg atrazine/L for 28 days. Medaka were exposed to mean measured concentrations of 9.4, 48, 74, 97, and 244 μg atrazine/L for 28 or 29 days. Fish were evaluated for survival, fecundity, fertility, total length, wet weight, secondary sex characteristics, gonadosomatic index (GSI) (P. promelas only), plasma or hepatic vitellogenin (VTG), and histopathology of gonads. General observations of health and behaviour were also conducted. There were no statistically significant effects (i.e., p < 0.05) of atrazine on survival, size, reproduction, behaviour, GSI, VTG, or secondary sex characteristics in either species at any exposure level. In fathead minnows, there were no histopathological findings associated with atrazine exposure in male fish, but there was an increased proportion of Stage 4.0 ovaries accompanied by an increase in proportion of Grade 3 post-ovulatory follicles in females of the 105 μg/L treatment group. Without a concomitant increase in oocyte atresia, neither of these findings are considered adverse for the health of the fish. In medaka, there were no significant effects of atrazine exposure on histopathology in either sex. These data support current weight-of-evidence assessments that atrazine does not cause direct adverse effects on fish reproduction at environmentally realistic concentrations.
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http://dx.doi.org/10.1016/j.chemosphere.2018.04.068DOI Listing
August 2018

Fish short-term reproduction assay with atrazine and the Japanese medaka (Oryzias latipes).

Environ Toxicol Chem 2017 09 23;36(9):2327-2334. Epub 2017 Mar 23.

Syngenta Crop Protection, Greensboro, North Carolina, USA.

Breeding groups of Japanese medaka (Oryzias latipes) were exposed to atrazine at measured concentrations of 0.6, 5.5, and 53 μg/L for 35 d. Evaluated endpoints included survival, fecundity, fertility, growth (weight and length), behavior, secondary sex characteristics (anal fin papillae), gonad histopathology, and hepatic vitellogenin. No statistically significant effects of atrazine exposure on survival and growth of medaka were noted during the test, and mean survival was ≥97.5% in all treatment groups on day 35. No significant effects of atrazine exposure on reproduction were observed. The number of mean cumulative eggs produced in the negative control and the 0.6, 5.5, and 53 μg/L treatment groups was 7158, 6691, 6883, and 6856, respectively. The mean number of eggs per female reproductive day was 40.9, 38.2, 40.2, and 39.2, respectively. There were also no dose-dependent effects on mean anal fin papillae counts among male fish or expression of vtg-II in males or females. In addition, atrazine exposure was not related to the developmental stage of test fish, with testes stages ranging from 2 to 3 in all groups and ovaries ranging from stage 2 to 2.5. Overall, exposure to atrazine up to 53 µg/L for 35 d did not result in significant, treatment-related effects on measured endpoints related to survival, growth, or reproduction in Japanese medaka. Environ Toxicol Chem 2017;36:2327-2334. © 2017 SETAC.
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http://dx.doi.org/10.1002/etc.3769DOI Listing
September 2017

Mitochondrial efficiency and exercise economy following heat stress: a potential role of uncoupling protein 3.

Physiol Rep 2017 Feb;5(3)

Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico.

Heat stress has been reported to reduce uncoupling proteins (UCP) expression, which in turn should improve mitochondrial efficiency. Such an improvement in efficiency may translate to the systemic level as greater exercise economy. However, neither the heat-induced improvement in mitochondrial efficiency (due to decrease in UCP), nor its potential to improve economy has been studied. Determine: (i) if heat stress in vitro lowers UCP3 thereby improving mitochondrial efficiency in C2C12 myocytes; (ii) whether heat acclimation (HA) in vivo improves exercise economy in trained individuals; and (iii) the potential improved economy during exercise at altitude. In vitro, myocytes were heat stressed for 24 h (40°C), followed by measurements of UCP3, mitochondrial uncoupling, and efficiency. In vivo, eight trained males completed: (i) pre-HA testing; (ii) 10 days of HA (40°C, 20% RH); and (iii) post-HA testing. Pre- and posttesting consisted of maximal exercise test and submaximal exercise at two intensities to assess exercise economy at 1600 m (Albuquerque, NM) and 4350 m. Heat-stressed myocytes displayed significantly reduced UCP3 mRNA expression and, mitochondrial uncoupling (77.1 ± 1.2%, P < 0.0001) and improved mitochondrial efficiency (62.9 ± 4.1%, P < 0.0001) compared to control. In humans, at both 1600 m and 4350 m, following HA, submaximal exercise economy did not change at low and moderate exercise intensities. Our findings indicate that while heat-induced reduction in UCP3 improves mitochondrial efficiency in vitro, this is not translated to in vivo improvement of exercise economy at 1600 m or 4350 m.
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http://dx.doi.org/10.14814/phy2.13054DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5309567PMC
February 2017

Heat acclimation: Gold mines and genes.

Temperature (Austin) 2016 27;3(4):527-538. Epub 2016 Sep 27.

University of New Mexico, Department of Exercise Sciences , Albuquerque, NM, USA.

The underground gold mines of South Africa offer a unique historical setting to study heat acclimation. The early heat stress research was conducted and described by a young medical officer, Dr. Aldo Dreosti. He developed practical and specific protocols to first assess the heat tolerance of thousands of new mining recruits, and then used the screening results as the basis for assigning a heat acclimation protocol. The mines provide an interesting paradigm where the prevention of heat stroke evolved from genetic selection, where only Black natives were recruited due to a false assumption of their intrinsic tolerance to heat, to our current appreciation of the epigenetic and other molecular adaptations that occur with exposure to heat.
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http://dx.doi.org/10.1080/23328940.2016.1240749DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5198811PMC
September 2016

Treadmill exercise within lower body negative pressure protects leg lean tissue mass and extensor strength and endurance during bed rest.

Physiol Rep 2016 08;4(15)

University of California, San Diego, California.

Leg muscle mass and strength are decreased during reduced activity and non-weight-bearing conditions such as bed rest (BR) and spaceflight. Supine treadmill exercise within lower body negative pressure (LBNPEX) provides full-body weight loading during BR and may prevent muscle deconditioning. We hypothesized that a 40-min interval exercise protocol performed against LBNPEX 6 days week(-1) would attenuate losses in leg lean mass (LLM), strength, and endurance during 6° head-down tilt BR, with similar benefits for men and women. Fifteen pairs of healthy monozygous twins (8 male and 7 female pairs) completed 30 days of BR with one sibling of each twin pair assigned randomly as the non-exercise control (CON) and the other twin as the exercise subject (EX). Before and after BR, LLM and isokinetic leg strength and endurance were measured. Mean knee and ankle extensor and flexor strength and endurance and LLM decreased from pre- to post-BR in the male CON subjects (P < 0.01), but knee extensor strength and endurance, ankle extensor strength, and LLM were maintained in the male EX subjects. In contrast, no pre- to post-BR changes were significant in the female subjects, either CON or EX, likely due to their lower pre-BR values. Importantly, the LBNPEX countermeasure prevents or attenuates declines in LLM as well as extensor leg strength and endurance. Individuals who are stronger, have higher levels of muscular endurance, and/or have greater LLM are likely to experience greater losses during BR than those who are less fit.
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http://dx.doi.org/10.14814/phy2.12892DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985554PMC
August 2016

HSP72 Up-regulation with heat acclimation.

Temperature (Austin) 2016 Jan-Mar;3(1):28-30. Epub 2016 Mar 30.

Central Michigan University, School of Health Sciences Mt. Pleasant , MI, USA.

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http://dx.doi.org/10.1080/23328940.2016.1148525DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861197PMC
May 2016

The effect of 10 days of heat acclimation on exercise performance in acute hypobaric hypoxia (4350 m).

Temperature (Austin) 2016 Jan-Mar;3(1):176-85. Epub 2015 Jul 25.

Department of Health, Exercise, and Sports Sciences, University of New Mexico , Albuquerque, NM, USA.

To examine the effect ("cross-tolerance") of heat acclimation (HA) on exercise performance upon exposure to acute hypobaric hypoxia (4350 m). Eight male cyclists residing at 1600 m performed tests of maximal aerobic capacity (VO2max) at 1600 m and 4350 m, a 16 km time-trial at 4350 m, and a heat tolerance test at 1600 m before and after 10 d HA at 40°C, 20% RH. Resting blood samples were obtained pre-and post- HA to estimate changes in plasma volume (ΔPV). Successful HA was indicated by significantly lower exercise heart rate and rectal temperature on day 10 vs. day 1 of HA and during the heat tolerance tests. Heat acclimation caused a 1.9% ΔPV, however VO2max was not significantly different at 1600 m or 4350 m. Time-trial cycling performance improved 28 sec after HA (p = 0.07), suggesting a possible benefit for exercise performance at acute altitude and that cross-tolerance between these variables may exist in humans. These findings do not clearly support the use of HA to improve exercise capacity and performance upon acute hypobaric hypoxia, however they do indicate that HA is not detrimental to either exercise capacity or performance.
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http://dx.doi.org/10.1080/23328940.2015.1072659DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4861181PMC
May 2016

The effect of insulin resistance and exercise on the percentage of CD16(+) monocyte subset in obese individuals.

Cell Biochem Funct 2016 Jun 30;34(4):209-16. Epub 2016 Mar 30.

Sociedade Brasileira de Fisiologia (SBFis), Programa Multicêntrico de Pós-graduação em Ciências Fisiológicas (PMPGCF), Brazil.

Unlabelled: Obesity is a low-grade chronic inflammation condition, and macrophages, and possibly monocytes, are involved in the pathological outcomes of obesity. Physical exercise is a low-cost strategy to prevent and treat obesity, probably because of its anti-inflammatory action. We evaluated the percentage of CD16(-) and CD16(+) monocyte subsets in obese insulin-resistant individuals and the effect of an exercise bout on the percentage of these cells. Twenty-seven volunteers were divided into three experimental groups: lean insulin sensitive, obese insulin sensitive and obese insulin resistant. Venous blood samples collected before and 1 h after an aerobic exercise session on a cycle ergometer were used for determination of monocyte subsets by flow cytometry. Insulin-resistant obese individuals have a higher percentage of CD16(+) monocytes (14.8 ± 2.4%) than the lean group (10.0 ± 1.3%). A positive correlation of the percentage of CD16(+) monocytes with body mass index and fasting plasma insulin levels was found. One bout of moderate exercise reduced the percentage of CD16(+) monocytes by 10% in all the groups evaluated. Also, the absolute monocyte count, as well as all other leukocyte populations, in lean and obese individuals, increased after exercise. This fact may partially account for the observed reduction in the percentage of CD16(+) cells in response to exercise. Insulin-resistant, but not insulin-sensitive obese individuals, have an increased percentage of CD16(+) monocytes that can be slightly modulated by a single bout of moderate aerobic exercise. These findings may be clinically relevant to the population studied, considering the involvement of CD16(+) monocytes in the pathophysiology of obesity. Copyright © 2016 John Wiley & Sons, Ltd.

Significance Of The Study: Obesity is now considered to be an inflammatory condition associated with many pathological consequences, including insulin resistance. It is proposed that insulin resistance contributes to the aggravation of the inflammatory dysfunction in obesity. The effect of obesity on the percentage of monocytes was previously observed in class II and III obese individuals who presented other alterations in addition to insulin resistance. In this study we observed that insulin-resistant obese individuals, but not insulin-sensitive ones, had an increased percentage of CD14(+) CD16(+) monocytes. This fact shows that a dysfunction of the monocyte percentage in class I obese individuals is only seen when this condition is associated with insulin resistance.
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http://dx.doi.org/10.1002/cbf.3178DOI Listing
June 2016

WISE 2005: Aerobic and resistive countermeasures prevent paraspinal muscle deconditioning during 60-day bed rest in women.

J Appl Physiol (1985) 2016 05 18;120(10):1215-22. Epub 2016 Feb 18.

Department of Orthopaedic Surgery, University of California, San Diego, California;

Microgravity-induced lumbar paraspinal muscle deconditioning may contribute to back pain commonly experienced by astronauts and may increase the risk of postflight injury. We hypothesized that a combined resistive and aerobic exercise countermeasure protocol that included spinal loading would mitigate lumbar paraspinal muscle deconditioning during 60 days of bed rest in women. Sixteen women underwent 60-day, 6° head-down-tilt bed rest (BR) and were randomized into control and exercise groups. During bed rest the control group performed no exercise. The exercise group performed supine treadmill exercise within lower body negative pressure (LBNP) for 3-4 days/wk and flywheel resistive exercise for 2-3 days/wk. Paraspinal muscle cross-sectional area (CSA) was measured using a lumbar spine MRI sequence before and after BR. In addition, isokinetic spinal flexion and extension strengths were measured before and after BR. Data are presented as means ± SD. Total lumbar paraspinal muscle CSA decreased significantly more in controls (10.9 ± 3.4%) than in exercisers (4.3 ± 3.4%; P < 0.05). The erector spinae was the primary contributor (76%) to total lumbar paraspinal muscle loss. Moreover, exercise attenuated isokinetic spinal extension loss (-4.3 ± 4.5%), compared with controls (-16.6 ± 11.2%; P < 0.05). In conclusion, LBNP treadmill and flywheel resistive exercises during simulated microgravity mitigate decrements in lumbar paraspinal muscle structure and spine function. Therefore spaceflight exercise countermeasures that attempt to reproduce spinal loads experienced on Earth may mitigate spinal deconditioning during long-duration space travel.
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http://dx.doi.org/10.1152/japplphysiol.00532.2015DOI Listing
May 2016

Health coaching for glaucoma care: a pilot study using mixed methods.

Clin Ophthalmol 2015 22;9:1931-43. Epub 2015 Oct 22.

Department of Ophthalmology, Duke University, Durham, NC, USA.

Introduction: Adherence to glaucoma medications is essential for successful treatment of the disease but is complex and difficult for many of our patients. Health coaching has been used successfully in the treatment of other chronic diseases. This pilot study explores the use of health coaching for glaucoma care.

Methods: A mixed methods study design was used to assess the health coaching intervention for glaucoma patients. The health coaching intervention consisted of four to six health coaching sessions with a certified health coach via telephone. Quantitative measures included demographic and health information, adherence to glaucoma medications (using the visual analog adherence scale and medication event monitoring system), and an exit survey rating the experience. Qualitative measures included a precoaching health questionnaire, notes made by the coach during the intervention, and an exit interview with the subjects at the end of the study.

Results: Four glaucoma patients participated in the study; all derived benefits from the health coaching. Study subjects demonstrated increased glaucoma drop adherence in response to the coaching intervention, in both visual analog scale and medication event monitoring system. Study subjects' qualitative feedback reflected a perceived improvement in both eye and general health self-care. The subjects stated that they would recommend health coaching to friends or family members.

Conclusion: Health coaching was helpful to the glaucoma patients in this study; it has the potential to improve glaucoma care and overall health.
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http://dx.doi.org/10.2147/OPTH.S92935DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4629983PMC
November 2015

Impact of creatine on muscle performance and phosphagen stores after immobilization.

Eur J Appl Physiol 2015 Sep 18;115(9):1877-86. Epub 2015 Apr 18.

Exercise Science Program, Marcella Niehoff School of Nursing, Loyola University Chicago, 1032 W. Sheridan Road, BVM Hall 8th Floor, Chicago, IL, 60660, USA,

Purpose: This study investigated the effect of creatine (CR) supplementation during cast-immobilization to preserve skeletal muscle total work, power and intramuscular phosphocreatine (PCr) kinetics during dynamic exercise.

Methods: Twenty-five active individuals (24 ± 4 years,) performed wrist flexion exercise within a 1.9 Tesla superconducting magnet before and after 1 week of cast-immobilization. An incremental protocol to fatigue and two constant load (CL1 and CL2) exercise bouts were performed. While casted, participants consumed either 20 g day(-1) of CR or a placebo (PLA). (31)P magnetic resonance spectroscopy was used to quantify in vivo intramuscular PCr levels.

Results: No significant group × time interaction effects were found for work or power throughout all exercise bouts. Total work was significantly reduced over time in both groups (p = 0.049) during the incremental exercise bout. Work production in CL1 tended (p = 0.073) to attenuate in the CR group, compared to PLA. No changes were observed in CL2. Baseline PCr significantly decreased with casting in PLA (PRE: 26.6 ± 6.3 vs. POST: 22.5 ± 5.6 mM kg(-1) wet muscle, p = 0.003). No change (p = 0.31) was observed in the CR group. Changes in work production were significantly correlated with changes in resting PCr in CR (r = -0.63, p = 0.021) but not PLA (r = -0.36, p = 0.26) group.

Conclusions: Results suggest decreases in short-term endurance may be due to alternations of PCr status and/or metabolism. More research is needed to fully determine the efficacy of CR supplementation during short-term immobilization.
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http://dx.doi.org/10.1007/s00421-015-3172-2DOI Listing
September 2015

Physician coaching to enhance well-being: a qualitative analysis of a pilot intervention.

Explore (NY) 2014 Nov-Dec;10(6):372-9. Epub 2014 Aug 22.

Department of Ophthalmology, Duke University, Durham, NC.

Context: Physicians in the United States increasingly confront stress, burnout, and other serious symptoms at an alarming level. As a result, there is growing public interest in the development of interventions that improve physician resiliency.

Objective: The aim of this study is to evaluate the perceived impact of Physician Well-being Coaching on physician stress and resiliency, as implemented in a major medical center.

Study Design: Semi-structured interviews were conducted with 11 physician-participants, and three coaches of a Physician Well-being Coaching pilot focused on three main areas: life context, impacts of coaching, and coaching process.

Participants: Interviewees were physicians who completed between three and eight individual coaching sessions between October 2012 and May 2013 through the Physician Well-being Coaching pilot program.

Analysis: Qualitative content analysis of the 11 physician interviews and three coach interviews using Atlas.ti to generate patterns and themes.

Results: Physician Well-being Coaching helped participants increase resilience via skill and awareness development in the following three main areas: (1) boundary setting and prioritization, (2) self-compassion and self-care, and (3) self-awareness. These insights often led to behavior changes and were perceived by physicians to have indirect but positive impact on patient care.

Conclusions: Devaluing self-care while prioritizing the care of others may be a significant, but unnecessary, source of burnout for physicians. This study suggests that coaching can potentially help physicians alter this pattern through skill development and increased self-awareness. It also suggests that by strengthening physician self-care, coaching can help to positively impact patient care.
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http://dx.doi.org/10.1016/j.explore.2014.08.007DOI Listing
July 2015

The effects of acute oral glutamine supplementation on exercise-induced gastrointestinal permeability and heat shock protein expression in peripheral blood mononuclear cells.

Cell Stress Chaperones 2015 Jan 26;20(1):85-93. Epub 2014 Jul 26.

Department of Health, Exercise, and Sport Science, University of New Mexico, Albuquerque, NM, 87131, USA,

Chronic glutamine supplementation reduces exercise-induced intestinal permeability and inhibits the NF-κB pro-inflammatory pathway in human peripheral blood mononuclear cells. These effects were correlated with activation of HSP70. The purpose of this paper is to test if an acute dose of oral glutamine prior to exercise reduces intestinal permeability along with activation of the heat shock response leading to inhibition of pro-inflammatory markers. Physically active subjects (N = 7) completed baseline and exercise intestinal permeability tests, determined by the percent ratio of urinary lactulose (5 g) to rhamnose (2 g). Exercise included two 60-min treadmill runs at 70 % of VO2max at 30 °C after ingestion of glutamine (Gln) or placebo (Pla). Plasma levels of endotoxin and TNF-α, along with peripheral blood mononuclear cell (PBMC) protein expression of HSP70 and IκBα, were measured pre- and post-exercise and 2 and 4 h post-exercise. Permeability increased in the Pla trial compared to that at rest (0.06 ± 0.01 vs. 0.02 ± 0.018) and did not increase in the Gln trial. Plasma endotoxin was lower at the 4-h time point in the Gln vs. 4 h in the Pla (6.715 ± 0.046 pg/ml vs. 7.952 ± 1.11 pg/ml). TNF-α was lower 4 h post-exercise in the Gln vs. Pla (1.64 ± 0.09 pg/ml vs. 1.87 ± 0.12 pg/ml). PBMC expression of IkBα was higher 4 h post-exercise in the Gln vs. 4 h in the Pla (1.29 ± 0.43 vs. 0.8892 ± 0.040). HSP70 was higher pre-exercise and 2 h post-exercise in the Gln vs. Pla (1.35 ± 0.21 vs. 1.000 ± 0.000 and 1.65 ± 0.21 vs. 1.27 ± 0.40). Acute oral glutamine supplementation prevents an exercise-induced rise in intestinal permeability and suppresses NF-κB activation in peripheral blood mononuclear cells.
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http://dx.doi.org/10.1007/s12192-014-0528-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4255255PMC
January 2015

Sex differences in heat shock protein 72 expression in peripheral blood mononuclear cells to acute exercise in the heat.

Int J Endocrinol Metab 2013 Oct 11;11(4):e8739. Epub 2013 Oct 11.

Department of Internal Medicine, The University of New Mexico, Albuquerque, USA.

Background: Heat shock protein 72 (Hsp72) is responsible for maintaining critical cellular function during heat stress. Hsp72 confers thermotolerance and may play a role in heat acclimation. Animal research suggests a difference between sexes in Hsp72 expression in response to exercise, however, human data is lacking.

Objectives: To determine sex differences in intracellular heat shock protein 72 (Hsp72) following exercise in the heat.

Patients And Methods: Nine non-heat acclimated women with normal menstrual cycles (VO2pk 58 ± 5 mL.kgFFM(-1).min(-1)) and nine non-heat acclimated men (VO2pk 60 ± 7 ml.kgFFM(-1).min(-1)) completed 2 treadmill bouts at 60% VO2pk for 60 min in a 42°C, 20% RH environment. Women were tested in follicular (fol) and luteal (lut) phases. The duplicate trials were separated by 12 days for men and women. Blood samples were drawn pre, immediately post, 1, and 4 hrs post-exercise.

Results: Men and women differed in their Hsp72 response after exercise (time X sex X trial interaction; P < 0.05). Men increased Hsp72 after exercise more than women. Both men and women produced less Hsp72 during trial 2 compared to trial 1. Estrogen (r = 0.24; P > 0.05) and progesterone (r = 0.27, P > 0.05) concentrations were not correlated with Hsp72.

Conclusion: Our findings suggest that men and women differ in their cellular stress response. Men up-regulated Hsp72 after a single bout of exercise in the heat, which persists for 12 days, suggesting an accumulation of Hsp72 which may lead to acquired cellular thermotolerance.
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http://dx.doi.org/10.5812/ijem.8739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3968984PMC
October 2013

WISE-2005: Countermeasures to prevent muscle deconditioning during bed rest in women.

J Appl Physiol (1985) 2014 Mar 23;116(6):654-67. Epub 2014 Jan 23.

Wyle Science, Technology, and Engineering Group, Houston, Texas;

The objectives of this study were to evaluate the efficacy of two separate countermeasures, exercise and protein supplementation, to prevent muscle strength and lean tissue mass losses during 60 days of bed rest (BR) in women and whether countermeasure efficacy was influenced by pre-BR muscular fitness (strength, endurance, tissue mass). Twenty-four women were assigned to an exercise (EX, n = 8), a no-exercise control (CON, n = 8), or a no-exercise protein supplementation group (PROT, n = 8). EX performed supine treadmill exercise within lower body negative pressure 3-4 days/wk and maximal concentric and eccentric supine leg- and calf-press exercises 2-4 days/wk. PROT consumed a diet with elevated protein content compared with CON and EX (1.6 vs. 1.0 g·kg(-1)·day(-1)). Knee and calf isokinetic strength and endurance, isotonic leg-press strength, and leg lean mass were measured before and after BR. Post-BR knee extensor strength and endurance, ankle strength, and leg lean mass were significantly greater and leg-press strength tended to be higher in EX than in CON and PROT. Post-BR measures in PROT were not different than those in CON. Exercise countermeasure efficacy was less, and strength, endurance, and leg lean mass losses in CON and PROT were greater, in subjects who were more fit pre-BR. An exercise protocol combining resistive and aerobic exercise training protects against losses in strength, endurance, and leg lean mass in women during BR, while a nutritional countermeasure without exercise was not effective. Exercise countermeasures may require individualization to protect higher levels of strength and endurance.
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http://dx.doi.org/10.1152/japplphysiol.00590.2013DOI Listing
March 2014

Effects of oral glutamine supplementation on exercise-induced gastrointestinal permeability and tight junction protein expression.

J Appl Physiol (1985) 2014 Jan 27;116(2):183-91. Epub 2013 Nov 27.

Department of Health, Exercise, and Sport Science, University of New Mexico, Albuquerque, New Mexico;

The objectives of this study are threefold: 1) to assess whether 7 days of oral glutamine (GLN) supplementation reduces exercise-induced intestinal permeability; 2) whether supplementation prevents the proinflammatory response; and 3) whether these changes are associated with upregulation of the heat shock response. On separate occasions, eight human subjects participated in baseline testing and in GLN and placebo (PLA) supplementation trials, followed by a 60-min treadmill run. Intestinal permeability was higher in the PLA trial compared with baseline and GLN trials (0.0604 ± 0.047 vs. 0.0218 ± 0.008 and 0.0272 ± 0.007, respectively; P < 0.05). IκBα expression in peripheral blood mononuclear cells was higher 240 min after exercise in the GLN trial compared with the PLA trial (1.411 ± 0.523 vs. 0.9839 ± 0.343, respectively; P < 0.05). In vitro using the intestinal epithelial cell line Caco-2, we measured effects of GLN supplementation (0, 4, and 6 mM) on heat-induced (37° or 41.8°C) heat shock protein 70 (HSP70), heat shock factor-1 (HSF-1), and occludin expression. HSF-1 and HSP70 levels increased in 6 mM supplementation at 41°C compared with 0 mM at 41°C (1.785 ± 0.495 vs. 0.6681 ± 0.290, and 1.973 ± 0.325 vs. 1.133 ± 0.129, respectively; P < 0.05). Occludin levels increased after 4 mM supplementation at 41°C and 6 mM at 41°C compared with 0 mM at 41°C (1.236 ± 0.219 and 1.849 ± 0.564 vs. 0.7434 ± 0.027, respectively; P < 0.001). GLN supplementation prevented exercise-induced permeability, possibly through HSF-1 activation.
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http://dx.doi.org/10.1152/japplphysiol.00646.2013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3921361PMC
January 2014

Exercise reduces cellular stress related to skeletal muscle insulin resistance.

Cell Stress Chaperones 2014 Mar 22;19(2):263-70. Epub 2013 Aug 22.

Exercise Physiology Laboratory, Healthy and Biological Sciences Faculty, Federal University of Jequitinhonha and Mucuri Valleys, Rua da Glória 187, Diamantina, 39100-100, Minas Gerais, Brazil.

This study sought to evaluate the effects of a single session of exercise on the expression of Hsp70, of c-jun N-terminal kinase (JNK), and insulin receptor substrate 1 serine 612 (IRS(ser612)) phosphorylation in the skeletal muscle of obese and obese insulin-resistant patients. Twenty-seven volunteers were divided into three experimental groups (eutrophic insulin-sensitive, obese insulin-sensitive, and obese insulin-resistant) according to their body mass index and the presence of insulin resistance. The volunteers performed 60 min of aerobic exercise on a cycle ergometer at 60 % of peak oxygen consumption. M. vastus lateralis samples were obtained before and after exercise. The protein expressions were evaluated by Western blot. Our findings show that compared with paired eutrophic controls, obese subjects have higher basal levels of p-JNK (100 ± 23 % vs. 227 ± 67 %, p = 0.03) and p-IRS-1(ser612) (100 ± 23 % vs. 340 ± 67 %, p < 0.001) and reduced HSP70 (100 ± 16 % vs. 63 ± 12 %, p < 0.001). The presence of insulin resistance results in a further increase in p-JNK (460 ± 107 %, p < 0.001) and a decrease in Hsp70 (46 ± 5 %, p = 0.006), but p-IRS-1(ser612) levels did not differ from obese subjects (312 ± 73 %, p > 0.05). Exercise reduced p-JNK in obese insulin-resistant subjects (328 ± 33 %, p = 0.001), but not in controls or obese subjects. Furthermore, exercise reduced p-IRS-1(ser612) for both obese (122 ± 44 %) and obese insulin-resistant (185 ± 36 %) subjects. A main effect of exercise was observed in HSP70 (p = 0.007). We demonstrated that a single session of exercise promotes changes that characterize a reduction in cellular stress that may contribute to exercise-induced increase in insulin sensitivity.
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http://dx.doi.org/10.1007/s12192-013-0453-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3933613PMC
March 2014

Palm Cooling and Heating Delays Fatigue During Resistance Exercise in Women.

J Strength Cond Res 2015 Aug;29(8):2261-9

1Department of Kinesiology and Recreation Administration, Humboldt State University, Arcata, California; 2School of Human Movement Studies, Charles Sturt University, Bathurst, Australia; 3Department of Health, Exercise, and Sports Sciences, University of New Mexico, Albuquerque, New Mexico; and 4Department of Orthopedics and Rehabilitation, University of New Mexico, Albuquerque, New Mexico.

We previously reported that cold application to the palms between sets of high-intensity bench press exercise produces an ergogenic effect in men. In this study, we hypothesized that palm cooling (PC) or heating during rest intervals between high-intensity weight training sets will increase total repetitions and exercise volume load (kilograms) in resistance trained female subjects in a thermoneutral (TN) environment. Eight female subjects (mean ± SD, age = 25 ± 6 years, height = 160 ± 6 cm, body mass = 56 ± 7 kg, 1-repetition maximum [1RM] = 52 ± 6 kg, weight training experience = 6 ± 2 years) completed 4 sets of 85% 1RM bench press exercise to failure, with 3-minute rest intervals. Exercise trials were performed in a counterbalanced order on 3 days, separated by at least 3 days in TN, Palm heating (PH), and PC conditions. Heating and cooling were applied by placing both hands in a hand cooling device with the hand plate set to 45° C for heating and 10° C for cooling. Data were analyzed using a 2-factor repeated-measures analysis of variance and Tukey's post hoc tests. Palm cooling repetitions were significantly higher than TN repetitions during the second set, and PH repetitions were significantly higher than those of TN during the fourth set. Total exercise volume load (kilograms) for both PC (1,387 ± 358) and PH (1,349 ± 267) were significantly higher than TN (1,187 ± 262). In women, both heating and cooling of the palms between sets of resistance exercise increased the total exercise volume load performed. This ergogenic response to a peripheral sensory input is consistent with the central governor theory of muscular fatigue.
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http://dx.doi.org/10.1519/JSC.0b013e31829cef4eDOI Listing
August 2015

PTSD symptom reduction with mindfulness-based stretching and deep breathing exercise: randomized controlled clinical trial of efficacy.

J Clin Endocrinol Metab 2013 Jul 29;98(7):2984-92. Epub 2013 May 29.

National Institutes of Health, Clinical Center, Bethesda, Maryland 20892, USA.

Context: Abnormal cortisol levels are a key pathophysiological indicator of post-traumatic stress disorder (PTSD). Endogenous normalization of cortisol concentration through exercise may be associated with PTSD symptom reduction.

Objective: The aim of the study was to determine whether mindfulness-based stretching and deep breathing exercise (MBX) normalizes cortisol levels and reduces PTSD symptom severity among individuals with subclinical features of PTSD.

Design And Setting: A randomized controlled trial was conducted at the University of New Mexico Health Sciences Center.

Participants: Twenty-nine nurses (28 female) aged 45-66 years participated in the study.

Intervention: Sixty-minute MBX sessions were conducted semiweekly for 8 weeks.

Main Outcome Measures: Serum cortisol was measured, and the PTSD Checklist-Civilian version (PCL-C) was performed at baseline and weeks 4, 8, and 16.

Results: Twenty-nine participants completed the study procedures, 22 (79%) with PTSD symptoms (MBX, n = 11; control, n = 11), and 7 (21%) without PTSD (BASE group). Eight-week outcomes for the MBX group were superior to those for the control group (mean difference for PCL-C scores, -13.6; 95% confidence interval [CI], -25.6, -1.6; P = .01; mean difference for serum cortisol, 5.8; 95% CI, 0.83, 10.8; P = .01). No significant differences were identified between groups in any other items. The changes in the MBX group were maintained at the 16-week follow-up (P = .85 for PCL-C; P = .21 for cortisol). Our data show that improved PTSD scores were associated with normalization of cortisol levels (P < .05).

Conclusions: The results suggest that MBX appears to reduce the prevalence of PTSD-like symptoms in individuals exhibiting subclinical features of PTSD.
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http://dx.doi.org/10.1210/jc.2012-3742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3701284PMC
July 2013

Mind-body practices for posttraumatic stress disorder.

J Investig Med 2013 Jun;61(5):827-34

Department of Health, Exercise, and Sports Sciences, University of New Mexico, Albuquerque, NM, USA.

Background: Mind-body practices are increasingly used to provide stress reduction for posttraumatic stress disorder (PTSD). Mind-body practice encompasses activities with the intent to use the mind to impact physical functioning and improve health.

Methods: This is a literature review using PubMed, PsycINFO, and Published International Literature on Traumatic Stress to identify the effects of mind-body intervention modalities, such as yoga, tai chi, qigong, mindfulness-based stress reduction, meditation, and deep breathing, as interventions for PTSD.

Results: The literature search identified 92 articles, only 16 of which were suitable for inclusion in this review. We reviewed only original, full text articles that met the inclusion criteria. Most of the studies have small sample size, but findings from the 16 publications reviewed here suggest that mind-body practices are associated with positive impacts on PTSD symptoms. Mind-body practices incorporate numerous therapeutic effects on stress responses, including reductions in anxiety, depression, and anger, and increases in pain tolerance, self-esteem, energy levels, ability to relax, and ability to cope with stressful situations. In general, mind-body practices were found to be a viable intervention to improve the constellation of PTSD symptoms such as intrusive memories, avoidance, and increased emotional arousal.

Conclusions: Mind-body practices are increasingly used in the treatment of PTSD and are associated with positive impacts on stress-induced illnesses such as depression and PTSD in most existing studies. Knowledge about the diverse modalities of mind-body practices may provide clinicians and patients with the opportunity to explore an individualized and effective treatment plan enhanced by mind-body interventions as part of ongoing self-care.
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http://dx.doi.org/10.2310/JIM.0b013e3182906862DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3668544PMC
June 2013

Regulatory coordination between two major intracellular homeostatic systems: heat shock response and autophagy.

J Biol Chem 2013 May 10;288(21):14959-72. Epub 2013 Apr 10.

Department of Internal Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA.

The eukaryotic cell depends on multitiered homeostatic systems ensuring maintenance of proteostasis, organellar integrity, function and turnover, and overall cellular viability. At the two opposite ends of the homeostatic system spectrum are heat shock response and autophagy. Here, we tested whether there are interactions between these homeostatic systems, one universally operational in all prokaryotic and eukaryotic cells, and the other one (autophagy) is limited to eukaryotes. We found that heat shock response regulates autophagy. The interaction between the two systems was demonstrated by testing the role of HSF-1, the central regulator of heat shock gene expression. Knockdown of HSF-1 increased the LC3 lipidation associated with formation of autophagosomal organelles, whereas depletion of HSF-1 potentiated both starvation- and rapamycin-induced autophagy. HSP70 expression but not expression of its ATPase mutant inhibited starvation or rapamycin-induced autophagy. We also show that exercise induces autophagy in humans. As predicted by our in vitro studies, glutamine supplementation as a conditioning stimulus prior to exercise significantly increased HSP70 protein expression and prevented the expected exercise induction of autophagy. Our data demonstrate for the first time that heat shock response, from the top of its regulatory cascade (HSF-1) down to the execution stages delivered by HSP70, controls autophagy thus connecting and coordinating the two extreme ends of the homeostatic systems in the eukaryotic cell.
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http://dx.doi.org/10.1074/jbc.M113.462408DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663517PMC
May 2013

Exercise regulation of intestinal tight junction proteins.

Br J Sports Med 2014 Jun 7;48(12):980-6. Epub 2012 Nov 7.

Department of Internal Medicine, University of New Mexico, Albuquerque, New Mexico, USA.

Gastrointestinal distress, such as diarrhoea, cramping, vomiting, nausea and gastric pain are common among athletes during training and competition. The mechanisms that cause these symptoms are not fully understood. The stress of heat and oxidative damage during exercise causes disruption to intestinal epithelial cell tight junction proteins resulting in increased permeability to luminal endotoxins. The endotoxin moves into the blood stream leading to a systemic immune response. Tight junction integrity is altered by the phosphoylation state of the proteins occludin and claudins, and may be regulated by the type of exercise performed. Prolonged exercise and high-intensity exercise lead to an increase in key phosphorylation enzymes that ultimately cause tight junction dysfunction, but the mechanisms are different. The purpose of this review is to (1) explain the function and physiology of tight junction regulation, (2) discuss the effects of prolonged and high-intensity exercise on tight junction permeability leading to gastrointestinal distress and (3) review agents that may increase or decrease tight junction integrity during exercise.
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http://dx.doi.org/10.1136/bjsports-2012-091585DOI Listing
June 2014

Effect of local cooling on short-term, intense exercise.

J Strength Cond Res 2013 Jul;27(7):2046-54

Department of Kinesiology, Washburn University, Topeka, Kansas, USA.

The widespread belief that local cooling impairs short-term, strenuous exercise performance is controversial. Eighteen original investigations involving cooling before and intermittent cooling during short-term, intensive exercise are summarized in this review. Previous literature examining short-term intensive exercise and local cooling primarily has been limited to the effects on muscle performance immediately or within minutes following cold application. Most previous cooling studies used equal and longer than 10 minutes of pre-cooling, and found that cooling reduced strength, performance and endurance. Because short duration, high intensity exercise requires adequate warm-up to prepare for optimal performance, prolonged pre-cooling is not an effective method to prepare for this type of exercise. The literature related to the effect of acute local cooling immediately before short duration, high intensity isotonic exercise such as weight lifting is limited. However, local intermittent cooling during short-term, high intense exercise may provide possible beneficial effects; first, by pain reduction, caused by an "irritation effect" from hand thermal receptors which block pain sensation, or second, by a cooling effect, whereby stimulation of hand thermal receptors or a slight lowering of blood temperature might alter central fatigue.
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http://dx.doi.org/10.1519/JSC.0b013e3182773259DOI Listing
July 2013

Space physiology VI: exercise, artificial gravity, and countermeasure development for prolonged space flight.

Eur J Appl Physiol 2013 Sep 19;113(9):2183-92. Epub 2012 Oct 19.

Department of Orthopedic Surgery, University of California San Diego, San Diego, CA 92103-8894, USA.

When applied individually, exercise countermeasures employed to date do not fully protect the cardiovascular and musculoskeletal systems during prolonged spaceflight. Recent ground-based research suggests that it is necessary to perform exercise countermeasures within some form of artificial gravity to prevent microgravity deconditioning. In this regard, it is important to provide normal foot-ward loading and intravascular hydrostatic-pressure gradients to maintain musculoskeletal and cardiovascular function. Aerobic exercise within a centrifuge restores cardiovascular function, while aerobic exercise within lower body negative pressure restores cardiovascular function and helps protect the musculoskeletal system. Resistive exercise with vibration stimulation may increase the effectiveness of resistive exercise by preserving muscle function, allowing lower intensity exercises, and possibly reducing risk of loss of vision during prolonged spaceflight. Inexpensive methods to induce artificial gravity alone (to counteract head-ward fluid shifts) and exercise during artificial gravity (for example, by short-arm centrifuge or exercise within lower body negative pressure) should be developed further and evaluated as multi-system countermeasures.
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http://dx.doi.org/10.1007/s00421-012-2523-5DOI Listing
September 2013

Thermotolerance and heat acclimation may share a common mechanism in humans.

Am J Physiol Regul Integr Comp Physiol 2011 Aug 25;301(2):R524-33. Epub 2011 May 25.

Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, New Mexico, USA.

Thermotolerance and heat acclimation are key adaptation processes that have been hitherto viewed as separate phenomena. Here, we provide evidence that these processes may share a common basis, as both may potentially be governed by the heat shock response. We evaluated the effects of a heat shock response-inhibitor (quercetin; 2,000 mg/day) on established markers of thermotolerance [gastrointestinal barrier permeability, plasma TNF-α, IL-6, and IL-10 concentrations, and leukocyte heat shock protein 70 (HSP70) content]. Heat acclimation reduced body temperatures, heart rate, and physiological strain during exercise/heat stress) in male subjects (n = 8) completing a 7-day heat acclimation protocol. These same subjects completed an identical protocol under placebo supplementation (placebo). Gastrointestinal barrier permeability and TNF-α were increased on the 1st day of exercise/heat stress in quercetin; no differences in these variables were reported in placebo. Exercise HSP70 responses were increased, and plasma cytokines (IL-6, IL-10) were decreased on the 7th day of heat acclimation in placebo; with concomitant reductions in exercise body temperatures, heart rate, and physiological strain. In contrast, gastrointestinal barrier permeability remained elevated, HSP70 was not increased, and IL-6, IL-10, and exercise body temperatures were not reduced on the 7th day of heat acclimation in quercetin. While exercise heart rate and physiological strain were reduced in quercetin, this occurred later in exercise than with placebo. Consistent with the concept that thermotolerance and heat acclimation are related through the heat shock response, repeated exercise/heat stress increases cytoprotective HSP70 and reduces circulating cytokines, contributing to reductions in cellular and systemic markers of heat strain. Exercising under a heat shock response-inhibitor prevents both cellular and systemic heat adaptations.
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http://dx.doi.org/10.1152/ajpregu.00039.2011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3154710PMC
August 2011
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